1. Field of the Invention
The present invention relates to a light beam scanning device and an image forming apparatus, and more particularly to a light beam scanning device that scans a scanned surface with a light beam and an image forming apparatus provided with the light beam scanning device.
2. Description of the Related Art
Japanese Patent Application Publication No. JP-2003-005114A (4454186-B1) discloses an image forming apparatus, in which the light beam is obliquely incident to a deflecting and reflecting surface of an optical deflector to achieve size reduction and cost reduction of the image forming apparatus. Compared with the case that the light beam is horizontally incident to the deflecting and reflecting surface of the optical deflector, the image forming apparatus with the obliquely incident light beam may suffer from drawbacks that (a) a scanning line curve tends to increase and (b) a diameter of a beam spot tends to increase.
In view of the above, there are various techniques to correct the scanning line curve. For example, Japanese Patent Application Publication No. JP-H11-014932-A (4057099-B1) discloses a method of producing a lens having a correction refractive surface that corrects the scanning line curve. Japanese Patent Application Publication No. JP-H11-038348-A (4098851-B1) discloses a scanning image forming optical system having a correction reflecting surface that corrects the scanning line curve.
Japanese Patent Application Publication No. JP-2007-248686-A discloses a light source device capable of reducing the scanning line curve and degradation in wavefront aberration. The light source device includes a light source retaining member. In the light source retaining member, plural light sources and plural lenses each of which is provided for each one of the light sources are arranged distant from one another in at least a sub-scanning direction such that they are integrally retained. Each light source is disposed such that the light beam emitted from the light source has an angle with respect to the sub-scanning direction, and the light source retaining member is tilted with respect to the sub-scanning direction.